Data reconciliation between a computer and a mobile data collection terminal

ABSTRACT

A method for communication between a host computer and at least one mobile computer terminal which provides an efficient way of running a computer network where the at least one mobile computer terminal operates at a remote site, has selectable operating characteristics, and is connected to the host computer through a wireless communications network, and wherein the host computer executes an application program in which data is entered from the at least one mobile computer terminal and processed by the application program, the method comprising the steps of: configuring the operating characteristics of the mobile computer terminal to correspond to data field characteristics required by the application program running on the host computer; utilizing the at least one mobile computer terminal to automatically acquire data at the remote site in response to a data acquisition program running on the at least one mobile computer terminal; transforming the acquired data into a data structure in the mobile computer terminal in accordance with said data field characteristics required by the application program running on the host computer; and transferring said data structure to the host computer over the wireless communications network. The method also provides for a way to ensure that the application program running on the host computer handles data received from the at least one mobile computer terminals when one of the mobile computer terminals goes out of range of the wireless network, comprising the steps of: establishing communications and association between a first of the at least one mobile computer terminals and a first access point on a local network; determining in said first of the at least one mobile computer terminals, that communications between said first of the at least one mobile computer terminals and all other access points have been impeded and switching to batch mode to continue data collection.

CROSS-REFERENCE TO RELATION APPLICATION

This application claims priority from U.S. Provisional Serial No.60/083,551, filed Apr. 29, 1998.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of computer data baseprocessing. More specifically, the present invention relates to dataformatting, data base updating, synchronization and reconciliationbetween a host or server computer and mobile data collection terminals.

2. The Background Art

Computer client/server systems have been designed which utilize a hostcomputer and one or more mobile terminals. The host computer may be amainframe computer, while the mobile terminals are usually hand held,less powerful portable computers. By using less powerful mobileterminals, it is possible to reduce the size and cost of each terminal.This can be accomplished by having systems which require the terminalsto emulate more sophisticated desktop terminals and perform onlyspecific tasks or processes required by the host computer.

One application such terminals are particularly suited for is datacollection. Bar code symbols or other forms of data may be entered at amobile terminal and then transferred to a host computer for processingor manipulation. There are many types of tasks that may be performed bymobile terminals, and data collection is only one example.

Additionally, data collection and other uses for mobile terminals maynot necessarily be stationary tasks. Many times, the user inputting thedata must move around in order to properly collect the data. Forexample, if a user wanted to perform inventory tasks, they may walkaround a warehouse full of boxes to count and visually inspect each box.Then they would have to return to a fixed mobile terminal to input thedata. It would be much more efficient if the user could bring the mobileterminal with him as he performed the inventory tasks and enter eachpiece of data as he receives it.

The advent of wireless technology and the miniaturization of thecomputer has allowed for palmtop or other small computers, running on awireless network, to be used in data collection and other tasks. Anexample of such a device is disclosed in Herrod et. al., U.S. Pat. No.5,604,516, hereby expressly incorporated by reference. The user maycarry the mobile terminal around with him and input data as necessary.

A mobile computer network is depicted in FIG. 1. Host computer 10 may beconnected to one or more mobile computer terminals 12, 14 through awireless communications network. Communication may be accomplished usingRF signals with the host computer connected in a local network alongwith stationary base stations (or “access points”) 16. The mobilecomputer terminals 12, 14 each have their own transmitter/receiver 18,20, respectively, which communicate to and from the access points. Theaccess points may be placed at various points around an area in whichthe mobile computer terminals can communicate with the host computer.For example, access points may be placed at various places around awarehouse if the mobile computer terminals are to be used for inventorytasks. When a mobile computer terminal 12 is in the range of one of theaccess points, connection and association may be established between thetransmitter/receiver 18 of the mobile computer terminal 12 and theaccess point 16. However, if a mobile computer terminal 14 is out ofrange of one of the access point 16, connection and association betweenthe transmitter/receiver 20 of the mobile computer and an access point16 is not established. Examples of similar communications systems aredisclosed in Tymes, U.S. Pat. No. 5,029,183, Tymes et al., U.S. Pat. No.5,280,498, Heiman et al., U.S. Pat. No. 5,528,621, and Tymes, U.S. Pat.No. 5,668,803, all hereby expressly incorporated by reference.

In Tymes, U.S. Pat. No. 5,029,183, a packet data communication networkis described where remote terminals may link to intermediate basestations through wireless RF communication wherein a packet istransmitted during a first time period and an acknowledge packet isreceived during a second time period occurring only at a selected timedelay after the first time period. In Tymes et al., U.S. Pat. No.5,280,498, a packet data communication network is described where remoteterminals may link to intermediate base stations through wireless RFcommunication wherein a packet is transmitted during a first time periodand an acknowledge packet is received during a second time periodoccurring only at a selected time delay after the first time period,with the acknowledge packet including a number sequence used to decodethe packet. In Tymes, U.S. Pat. No. 5,668,803, a packet datacommunication network is described where remote terminals may link tointermediate base stations through wireless RF communication wherein apacket is transmitted during a first time period and an acknowledgepacket is received during a second time period occurring only at aselected time delay after the first time period and a remote unit isalerted that a message is waiting to be picked up by including a messagein an acknowledge packet. In Heiman et al., U.S. Pat. No. 5,528,621, apacket data communication network is described where remote terminalsmay link to intermediate base stations through wireless RF communicationutilizing a frequency-hopping transmission method, with the basestations returning reply packets containing synchronization information.Communication may also be accomplished using other wirelesscommunications technologies.

It is common to run an application on the host computer 10 that requiresdata be entered in a certain format or sequence, or more specifically, aform or template having certain data entry fields within the applicationfills a host database 22 with data collected on the mobile computerterminals. A problem arises, however, in that the data collected on themobile computer terminals may not be in the proper format for simpleinsertion into data entry fields of the application running on the hostcomputer. For example, an inventory database application program maycurrently be running on the host computer and that application mayrequire that both an address field (in alphanumeric form) and a zip code(in numeric form) be filled for items in inventory. The data willeventually be stored in a host database 22. This data may be acquired byscanning bar code symbols off of each item in inventory. When the userscans the bar code symbols into the mobile computer terminal, theterminal may have no way of knowing in what order the application isrequesting the data entry fields be filled (e.g. does he enter addressthen zip code or zip code then address?).

Additionally, the mobile computer terminal may not know what types ofdata to collect. In the above example, it may not know if it is supposedto accept address and zip code data, or address and phone number data.

In the past, these problems were remedied using one of two approaches.First, the mobile computer terminal could be set up in advance to acceptonly certain types of data, and only in a specific order. For example,the mobile computer terminal may be set up to receive only address andzip code information, and only in that order. This approach, however,limits the flexibility of the system in that once the mobile computerterminal is set up, it may be difficult or impossible to alter the inputtypes. A problem occurs if the user suddenly decides that the name ofthe product should be entered as well, or that the zip code is no longernecessary.

The second approach to these problems is to run a special application orapplications on the mobile computer terminal. This application couldconvert the data into the proper format, or alter the ordering of thereceived data to match that of the requirements of the applicationrunning on the host computer. This approach, however, uses up valuableprocessing power and memory space on the mobile computer terminal.

Another problem that arises in such wireless computer networks occurswhen a user gets cut off from the network. The most common cause of thisproblem is when a user walks to a point that is out of range of thewireless transmitter/receivers or access points. However, this problemmay also be encountered due to electromagnetic interference as well asother problems that may interfere with the wireless network.

These interruptions can cause serious problems in the case of wirelessdata collection. If the mobile computer terminal is used to collect dataand transmit data to a host computer, and an interruption occurs, themobile computer terminal may continue to transmit its information. Thismay result in the loss of information since the data transmitted duringthis interruption is never received by the host computer. This may causedrastic consequences. For example, if the host computer is running aninventory application, the data lost during the interruption causes theinventory count to be incorrect. Additionally, it may be difficult orimpossible to determine at what point the interruption occurred or whichdata was being input at that time, so the entire inventory procedure mayhave to be restarted due to even a short interruption in the wirelessnetwork.

Another problem that potentially arises when a user gets cut off fromthe network occurs where data collected by the mobile terminal is timesensitive. For example, in a wireless computer network set up for a taxiservice, each taxicab may periodically send information as to itslocation to a host computer for use in aiding in dispatching. Supposeconnection with one of the taxicabs is broken at time t₁, and thetaxicab checks in with its location at time t₂. Then at time t₃,connection is re-established. The data sent to the host computer willrepresent the location of the taxicab at time t₂, but the host computerwill not know if the data it receives it receives represents thelocation of the taxi-cab at time t₂ or t₃. This may be referred to as a“data freshness” problem.

Another potential “data freshness” problem occurs in the case where themobile data terminals may be sending data which “competes” with datafrom other mobile data terminals. An example of this is the case wherethe host computer maintains an inventory list of manufactured goods andthe mobile computer terminals are used to make sales of those goods andreserve the goods for shipment. If there exist only ten manufacturedunits of a specific good (as tracked by the host computer database), anda first mobile computer terminal processes a sale for ten units of aspecific good at time t₁, while a second mobile computer terminalprocesses a sale for ten units for a specific good at time t₂, thenideally, the customer from the sale on the first mobile computerterminal will have his goods shipped immediately, while the customerfrom the sale on the second mobile computer terminal will have his goodsplaced on backorder until more of the goods can be manufactured.However, if the first mobile computer terminal went out of range betweent₁ and t₂, and connection was not re-established until after t₂, thenthe wrong customer will have his goods backordered.

OBJECTS OF THE INVENTION

It is therefore an object of the present invention to provide anapplication that can easily handle the formatting and ordering issuesthat arise when data is input into a mobile computer terminal foreventual incorporation into an application located on a host computer.

It is a further object of the present invention to provide anapplication that prevents the loss of data when interruptions in thewireless network occur.

It is a further object of the present invention to provide anapplication that can easily handle freshness issues.

BRIEF DESCRIPTION OF THE INVENTION

A method for communication between a host computer and at least onemobile computer terminal which provides an efficient way of running acomputer network where the at least one mobile computer terminaloperates at a remote site, has selectable operating characteristics, andis connected to the host computer through a wireless communicationsnetwork, and wherein the host computer executes an application programin which data is entered from the at least one mobile computer terminaland processed by the application program, the method comprising thesteps of: configuring the operating characteristics of the mobilecomputer terminal to correspond to data field characteristics requiredby the application program running on the host computer; utilizing theat least one mobile computer terminal to automatically acquire data atthe remote site in response to a data acquisition program running on theat least one mobile computer terminal; transforming the acquired datainto a data structure in the mobile computer terminal in accordance withsaid data field characteristics required by the application programrunning on the host computer; and transferring said data structure tothe host computer over the wireless communications network.

The method also provides for a way to ensure that the applicationprogram running on the host computer handles data received from the atleast one mobile computer terminals when one of the mobile computerterminals goes out of range of the wireless network, comprising thesteps of: establishing communications and association between a first ofthe at least one mobile computer terminals and a first access point on alocal network; determining in said first of the at least one mobilecomputer terminals, that communications between said first of the atleast one mobile computer terminals and all other access points havebeen impeded and switching to batch mode to continue data collection.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a block diagram illustrating a mobile computer network.

FIG. 2 is a flow diagram depicting a method for communication between ahost computer and at least one mobile computer terminal in accordancewith a first embodiment of the present invention.

FIG. 3 is a flow diagram depicting a method for communication between ahost computer and at least one mobile computer terminal designed toaccept bar code symbols as input in accordance with a second embodimentof the present invention.

FIG. 4 is a flow diagram depicting a method for communication between ahost computer and at least one mobile computer terminal third embodimentof the present invention.

FIG. 5 is a flow diagram depicting a method for communication between ahost computer and at least one mobile computer terminal designed toaccept bar code symbols as input in accordance with a second embodimentof the present invention.

FIG. 6 is a block diagram depicting another embodiment of the presentinvention.

FIG. 7 is a flow diagram of a batch mode method of the invention.

FIG. 8 is a block diagram illustrating another embodiment of the presentinvention.

FIG. 9 is a block diagram illustrating another embodiment of the presentinvention.

FIGS. 10A, 10B, and 10C are top, side and perspective views thatillustrate another embodiment of the present invention.

FIG. 11 is a perspective view illustrating how the information on thememory chip is transferred to a host computer.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Those of ordinary skill in the art will realize that the followingdescription of the present invention is illustrative only and not in anyway limiting. Other embodiments of the invention will readily suggestthemselves to such skilled persons.

FIG. 2 is a flow diagram depicting the typical data flow between asender and a receiver in a network environment. At 30, an applicationsends information to a user buffer 32, which is then read back usingprotocol modules 34. The data is then buffered through a kernal 36before sent through an interface 38 to a network media access control(MAC) 40. Similarly, when data is received by a Network MAC 42 in aninterface 44, it is subsequently buffered through a kernal 46, read outby protocol modules 48, passed into a user buffer 50 and eventually usedby an application 52.

Data is generally passed through a network in the form of packets. Eachpacket contains a header containing various information to be used thehardware and software associated with a network in determining how tohandle each packet. One such packet is depicted in FIG. 3, including aheader portion 60 and a data portion 62.

FIG. 4 depicts a method for communication between a host computer and atleast one mobile computer terminal in accordance with a first embodimentof the present invention. This embodiment allows the host computerapplication to switch from application to application, and to implementnew applications, without having the mobile computer terminal set up inadvance to handle a specific formatting scheme.

At step 80, the operating characteristics of the at least one mobilecomputer terminal are configured to correspond to data fieldcharacteristics required by the application program running on the hostcomputer. At step 82, the at least one mobile computer terminal isutilized to automatically acquire data at the remote site in response toa data acquisition program running on the at least one mobile computerterminal. At step 84, the acquired data is transformed into a datastructure in the mobile computer terminal in accordance with the datacharacteristics required by the application program running on the hostcomputer. Finally, at step 86, the data structure is transferred to thehost computer over a wireless network.

FIG. 5 depicts a method for communication between a host computer and atleast one mobile computer terminal designed to accept bar code symbolsas input in accordance with a second embodiment of the presentinvention. This may include utilizing one-dimensional bar code symbols(as known in the art) as well as two-dimensional bar code symbols, suchas PDF417 bar code symbol. Two dimensional bar code symbols generallyreduce the height of traditional one-dimensional symbols, and thenstacking distinct rows of such one dimensional symbols. Therefore,two-dimensional bar code symbols can store much more information thantraditional one-dimensional bar code symbols (a single PDF417 symbol maycarry up to 1.1 kilobytes of machine readable data in a space no largerthan a standard bar code symbol). Additionally, unlike traditionalone-dimensional bar code symbols, which represent a pointer or addressto a database, PDF417 symbols are the database itself.

A PDF417 symbol contains several fields, each field separated from thenext field by a character. It is then possible for an applicationprogram to properly parse the data obtained from the bar code symbolsinto the fields of the application for eventual entry into the database.

Referring to FIG. 5, at step 100, the operating characteristics of theat least one mobile computer terminal are configured to correspond todata field characteristics required by the application program runningon the host computer. This may comprise configuring the operatingcharacteristics so the mobile computer terminal acts as a terminalemulator as is known in the prior art. Commands are sent from the hostto the mobile computer terminal indicating which in which mode ofemulation the terminal should be. For example, it may be advantageous tohave a bar code scanning system which is capable of scanning severaldifferent types of bar code symbols. Therefore, the host may send a “0”if PDF417 scanning should be disabled (for scanning one dimensional barcode symbols). It may send a “1” if the terminal should be in contiguousmode only, where scanned PDF417 bar code symbols are a single block inan input field, limited to 500 bytes or less. It may send a “2” if theterminal should be in large mode only, which allows scanning of singlePDF417 bar code symbols larger than 500 bytes and multiple, linkedPDF417 bar code symbols to form one contiguous data block by storing thedata in a file on a RAM disk on the terminal which is sent to the hostcomputer as a single file. It may send a “3” if the terminal should bein separator mode only, which allows the data scanned from one PDF417bar code symbol to fill in a multiple field terminal emulation screenform by the host examining the bar code symbol for a separator characterto indicate where the data breaks are to fill the fields. The terminalmay then respond by sending a message to the host when it has receivedthe command mode information and is ready to begin scanning data.

At step 102, the at least one mobile computer terminal is utilized toautomatically acquire data from bar code symbols at the remote site inresponse to a data acquisition program running on the at least onemobile computer terminal. How the data is acquired depends on how theterminal was configured (in the case of PDF417 bar code symbol readers,which mode the terminal is acting in). An additional step may be addedhere for validity checking. This permits the system to make sure all ofthe fields in the scanned bar code symbol and the application match. Aseparator mode PDF417 bar code symbol that is scanned in may contain tenfields, while the application may contain only nine. The user could thenbe alerted that the bar code symbol is in the wrong format (or thatthere was an error in scanning) to prevent erroneous data from beingentered into the application. At step 104, the acquired data istransformed into a data structure in the mobile computer terminal inaccordance with the data characteristics required by the applicationprogram running on the host computer. Finally, at step 106, the datastructure is transferred to the host computer over a wireless network.

FIG. 6 depicts another embodiment of the present invention. It ispossible to avoid the potential loss of data that occurs when a mobilecomputer terminal goes out of range of the access points orcommunication is otherwise impeded by equipping each mobile computerterminal 120, 122 with a database 124, 126. When the mobile computerterminal goes out of range of all the access points 128, all datacollected during that time is stored in the mobile computer terminaldatabase 124, 126. When the mobile computer terminal re-establishes aconnection, the data collected may be uploaded to the host computer 130via the transmitter/receiver 132, 134 for eventual storage in the hostdatabase 136 without any loss of data. This process may be referred toas switching to batch mode. This method is depicted in FIG. 7.

At step 140, communications and association between a first of the atleast one mobile computer terminals and a first access point on a localnetwork is established. At this point, the mobile computer terminalbecomes part of the network and is able to transmit all of the data itreceives directly to the host computer as soon as it receives it. Atstep 142, the at least one mobile computer terminal periodically checksif communications between the first of the at least one mobile computerterminals and the access point have been impeded. This may beasynchronous polling based on the detection of RF broadcast signals.Basically, the terminal listens and if it doesn't hear anything from theaccess point then it assumes communications have been impeded. At step144, if communications not been impeded, the process returns to step 142to continue periodically scanning for communications. If communicationshave been impeded, however, the process moves to step 146, where it isdetermined whether or not communications and association can beestablished between the first of the at least one mobile computerterminals and one of the other access points on the local network. Ifthis can be accomplished immediately, there will likely be no loss ofdata. However, if communications and association cannot be establishedwith any of the access points on the local network, the mobile computerterminal is cut off from the network, and there is a potential for theloss of important data.

At step 148, the transmission of data from the first of the at least onemobile computer terminals is halted. Then at step 150, any new datareceived by the first of the at least one mobile computer terminals isstored in memory in the mobile computer terminal. This prevents any datafrom being lost. Information regarding the freshness of the data is alsostored at this point. This may comprise time stamping the data using anextra field in the data structure to store information as to the precisetime the data was received. The process then returns to step 146, wherecommunications and association with any of the access points on thelocal network is again attempted. This loop continues untilcommunications are re-established. Then at step 152, synchronization andreconciliation is performed to update the information stored in themobile computer terminal to the host computer, along with the datafreshness information so that the host computer may make properdeterminations as to the data's reliability and ranking.

Synchronization and reconciliation may involve comparing the database onthe mobile computer terminal with the database on the host computer, andupdating information on both databases accordingly. For example, in theinventory example, if a sale was made on the mobile computer terminalduring a period when the terminal was out of range, the host computerdatabase will have to be updated with the number of units sold duringthe synchronization and reconciliation stage. Similarly, the mobilecomputer terminal database will have to be updated with informationabout the current inventory in case the inventory was adjusted (throughsales from other mobile computer terminals or for other reasons) duringthe period that the terminal was out of range.

FIG. 8 is a diagram illustrating another embodiment of the presentinvention, utilizing other equipment in place of mobile computerterminals. This may include such peripherals as cellular phones 170,pagers 172, personal digital assistants 174, desktop computers 176, faxmachines 178, phones 180 and voice mail machines 182. All communicatethrough one or more wireless networks 184, 186 to a host computer 188.

Another potential piece of equipment that may be used in place of or inconjunction with a mobile computer terminal is a portablemulti-technology card reader. Currently, there are several differenttypes of cards that require scanning or reading in order to access dataor authenticate the card. These include credit cards, driver's licenses,military identifications, and so on. Currently, the most popular type ofcard/scanning method is the swipe card. In these systems, the card iswiped through a machine which reads information off a magnetic stripe onthe card. The information, however, may be encoded in many differentways. Additionally, there are several new types of cards emerging in themarketplace, including smart card and biometrics cards. Therefore, inanother embodiment of the present invention, at least one of the networkdevices is a portable, multi-technology card reader capable of scanningany type of card. A host computer may then be configured to readspecific types of cards and encoding schemes, such as PDF417 for cardsand documents, magnetic stripe cards, smart cards, and evenfingerprints. This allows for easy upgradeability when a new cardtechnology or new encoding system is designed. The portable nature ofthe reader also permits more uses than previous card readers. Forexample, instead of a police officer taking a driver's license off adetained motorist and swiping it though a machine in his patrol car, hemay instead simply scan the card using his portable scanner right at themotorist's car.

FIG. 9 is a diagram illustrating another embodiment of the presentinvention. This embodiment is similar to the one in FIG. 6. Here,however, the host computer has been removed, so the network allowsdirect communication from one peripheral 190 to another.

FIGS. 10A, 10B, 10C, and 11 illustrate another embodiment of the presentinvention. FIG. 10A is a diagram depicting a top view of a portablescanning device that may be used to scan and store data. Scanner 200 hasa keyhole 202 for easy attachment to a keychain. By allowing the user toplace the scanner on a keychain, the portability of the scannerincreases, as it is much easier for a user to carry it around withoutlosing what is potentially an expensive piece of equipment. The scanneris positioned so that the bar code symbol is in front of the scannerface 204. Then button 206 is depressed and the symbol is scanned, withthe data being stored in memory contained in the scanner. FIG. 10B is adiagram depicting a side view of the scanner. In this view, a keychainring 208 with a key 210 attached is shown attached to the scanner 200.FIG. 10 is a diagram depicting a perspective view of the scanner. FIG.11 is a diagram illustrating how the information on the memory chip istransferred to a host computer. The scanner 200 may be placed in a baseunit 212, which may be connected to a computer terminal. This allows theinformation from the memory in the scanner 200 to be read out andtransferred to whatever application the user deems necessary.

In another embodiment of the present invention, each mobile computerterminal may have a separate network address along with a display screencapable displaying a graphical image in a hypertext language (such asHTML). The host computer (or base unit, depending on the implementation)may have a second network address. The base unit may then transmit amessage to the network address corresponding to the mobile computerterminal, the message being represented by a graphical image in ahypertext language. The mobile computer terminal may then interpret themessage and automatically display the graphical image on the display.

This embodiment may be very helpful in such applications as pagers. Eachof the pagers may be the mobile computer terminal with a display. Whenthe user is paged, the display turns on revealing a hypertext languagepage. The page may contain information or graphics that the user shouldlook at, or it may also contain a menu, wherein the user may select andbe transferred to other web pages containing information. Using thismechanism, it is possible to use the pager for all sorts of differentapplications, such as receiving alphanumeric messages from familymembers, getting periodic updates on stock quotes or sports scores, orviewing graphical files sent from a business colleague. To that end, themobile computer terminal may include a liquid crystal display (LCD). TheLCD could instead be used to display the current time or date if thedesigner so wishes. The display of time and date would be most practicalin an embodiment used with a keychain.

The mobile computer terminals may also be configured as other commonlyused peripherals, such as wireless IP phones. An example of this is theNetVision® wireless IP phone system from Symbol Technologies, Inc.

One problem that may arise in the utilization of batch mode, is that itis possible for resynchronization to take a great deal of time. Thisnormally occurs when the user does not realize that he is out of range,and continues to input data into the mobile computer terminal as if itwas still transmitting to the host computer. While the batch mode designprevents the loss of data, the more data that is entered during this“down time”, the longer resynchronization will take when the mobilecomputer terminal is brought back into range.

To remedy this problem, the mobile computer terminal may be configuredwith an application that alerts the user when the mobile computerterminal goes out of range. This allows the user to realize that he isout of range before he inputs data into the terminal. This applicationmay be stored in firmware or a similar medium, where it may periodicallycheck to make sure that there is still a valid link to an access point.Then, if the link has been broken, a message may be flashed on thedisplay, such as “out of range”. The user may then have discretion as towhether to input the data and have it stored in batch mode, or waituntil the mobile computer terminal is brought back into range, whichwould save on resynchronization time.

Another problem that arises in the use of batch mode occurs when it isnecessary mobile computer terminal to send a message at a particulartime. While this application has dealt mostly with the case where amobile computer terminal cannot communicate with an access point becauseit is out of range, it should be recognized that the mobile computerterminal may not be able to communicate with an access point simplybecause it is in a “sleep mode. It is common for mobile computerterminals to have power conservation systems in order to save batterypower. It is therefore typical for a mobile computer terminal to go intoa “sleep” mode, where all its processing functions are shut down, whenthe mobile computer terminal is not used for a certain period of time.This presents a problem in cases where it is necessary for the mobilecomputer terminal to send a message at a certain time.

One example of this is in the limited leasing of Internet Protocol (IP)addresses. Generally, mobile computer terminals are granted an IPaddress on a network for only a limited amount of time. This is becausethe number of possible IP addresses is limited and most mobile computerterminals will only be using the network for a limited amount of time.Typically, a server assigns an IP address to the mobile computerterminal for a limited amount of time, and then specifies that if theuser requires additional time, the user must beg for an extension at anappropriate time. For example, the user may be required to beg for anextension at a time exactly halfway through the initial leased period.If the use does not beg for an extension at that time, he may beg for anextension at a time halfway through the remaining time (¾ of the waythrough the initial leased period), and if he doesn't beg at this time,at halfway through the remaining time (⅞ of the way through the initialleased period) and so on. At one minute remaining, the DHCP server maygive up and disconnect the user.

The problem arises when the mobile computer terminal is in “sleep” modewhen the time for begging arrives. This problem may be remedied byutilizing a timer or clock in the mobile computer terminal. The computerterminal may program the timer or clock before it goes to “sleep” towake it up at a specified time in order that it may send the beggingmessage. The timer or clock utilizes very little power, and most mobilecomputer terminals already contain such a clock or timer used for otherpurposes. The mobile computer first checks to determine if it is withinrange and, if not, displays a message to the user, resets the wake-uptimers for the next “scheduled” beg time, and then goes to sleep. If themobile computer is within range, it sends the lease renewal message andawaits a response from the DHCP leasing server. If the lease time hasexpired and the mobile computer cannot send a renewal or is not granteda renewal from the DHCP server, the mobile computer disconnects its IPattachment and no longer uses the granted leased address. When the“sleeping.” mobile computer who has surrendered its leased IP address iswoken up by the user, the user is informed about a lost IP address andis given an option to reconnect to its host by first accessing the DHCPserver for an IP address and reconnecting any active user application tothe host computer.

Additionally, while this application refers to IP addressing, there aremany other possible types of network addressing that this problem andsolution may arise in as well.

While embodiments and applications of this invention have been shown anddescribed, it would be apparent to those skilled in the art that manymore modifications than mentioned above are possible without departingfrom the inventive concepts herein. The invention, therefore, is not tobe restricted except in the spirit of the appended claims.

What is claimed is:
 1. A method for communication between a hostcomputer and at least one mobile computer terminal, wherein the at leastone mobile computer terminal operates at a remote site, has selectableoperating characteristics, and is connected to the host computer througha wireless communications network, and wherein the host computerexecutes an application program in which data is entered from the atleast one mobile computer terminal and processed by the applicationprogram, the method comprising the steps of: configuring the operatingcharacteristics of the mobile computer terminal to correspond to datafield characteristics required by the application program running on thehost computer, wherein said configuring step includes the step ofreceiving information about the data field characteristics required bythe application program running on the host computer from the hostcomputer over the wireless communications network; utilizing the atleast one mobile computer terminal to automatically acquire data at theremote site in response to a data acquisition program running on the atleast one mobile computer terminal; transforming the acquired data intoa data structure in the mobile computer terminal in accordance with saiddata field characteristics required by the application program runningon the host computer; and transferring said data structure to the hostcomputer over the wireless communications network.
 2. The method ofclaim 1, wherein said configuring step includes the step of configuringthe operating characteristics to accept bar code symbol information. 3.The method of claim 2, wherein said bar code symbol information isreceived from a bar code symbol scanner attached to the at least onemobile computer terminal.
 4. The method of claim 1, wherein saidconfiguring step includes the step of configuring the operatingcharacteristics to accept alphanumeric information.
 5. The method ofclaim 4, wherein said alphanumeric information is received from akeyboard attached to the at least one mobile computer terminal.
 6. Themethod of claim 1, wherein said at least one mobile computer terminal isa wireless IP phone.
 7. The method of claim 1, wherein said at least onemobile computer terminal contains a display for showing the currenttime.
 8. A method for communication between a host computer and at leastone mobile computer terminal, wherein the at least one mobile computerterminal operates at a remote site, has selectable operatingcharacteristics, and is connected to the host computer through awireless communications network, and wherein the host computer executesan application program in which data is entered from the at least onemobile computer terminal and processed by the application program, themethod comprising the steps of: configuring the operatingcharacteristics of the mobile computer terminal to correspond to datafield characteristics required by the application program running on thehost computer, wherein said configuring step includes the step ofreceiving information about the data field characteristics required bythe application program running on the host computer from the hostcomputer over the wireless communications network; utilizing the atleast one mobile computer terminal to automatically acquire from barcode symbols at the remote site in response to a data acquisitionprogram running on the at least one mobile computer terminal;transforming the acquired data into a data structure in the mobilecomputer terminal in accordance with said data field characteristicsrequired by the application program running on the host computer; andtransferring said data structure to the host computer over a wirelesscommunications network.
 9. The method of claim 8, wherein said bar codesymbols are received from a bar code symbol scanner attached to the atleast one mobile computer terminal.
 10. The method of claim 8, whereinsaid configuring step includes the step of configuring the operatingcharacteristics to accept alphanumeric information.
 11. The method ofclaim 10, wherein said alphanumeric information is received from akeyboard attached to the at least one mobile computer terminal.
 12. Themethod of claim 8, wherein said configuring step includes configuringthe operating characteristics of the mobile computer terminal so that itacts as a terminal emulator.
 13. The method of claim 8, wherein said barcode symbols are PDF417 bar code symbols.
 14. The method of claim 13,wherein said configuring step further includes the step of sendinginformation on the mode the mobile computer terminal should be in fromthe host computer to the mobile computer terminal.
 15. The method ofclaim 14, wherein said sending step includes the steps of: sending a “0”if the mode should be disabled PDF417 scanning; sending a “1” if themode should be contiguous mode only; sending a “2” if the mode should belarge mode only; and sending a “3” if the mode should be separator modeonly.
 16. The method of claim 8, wherein said configuring step furtherincludes the step of sending a signal from the mobile computer terminalto the host computer indicating that the mobile computer terminal isready to begin scanning when the information regarding the mode of themobile computer terminal is received and implemented by the mobilecomputer terminal.
 17. The method of claim 8, wherein said at least onemobile computer terminal includes a display for showing the currenttime.